Apple AirTunes private key extracted

http://www.mafipulation.org/blagoblig/2011/04/08#shairport

by PascalW • 15 years ago

371 94 15 years ago

Now that the AirTunes private key is known, it could allow for 3rd party software to act like AirTunes devices. If this for example would be implemented in XBMC, Plex, Boxee etc you could send audio from your IOS device straight to XBMC using IOS built-in Airplay support.

illumin84• 15 years ago

This is very cool. Do you know if this would work with AirPlay video streaming as well as audio? I can imagine it would be pretty cool to display video on any PC monitor.

Timothee3• 15 years ago

Is AirPlay encrypting streams though? There are a few apps that can playback AirPlay videos. Recently, I started to use a script that made Plex show up as an AirPlay target and it worked fine.

edit: NB: I'm not sure "encrypting" is the right word here… do not hesitate to correct me

illumin84• 15 years ago

I'm not sure - I've heard of an Android app that can send video to an AppleTV, but I haven't heard of an app that can receive video from an iOS device. If you know of one, I'd appreciate a link.

Timothee3• 15 years ago

Could someone explain the implications of this?

edit: it looks like it would allow another software to show up as an Airport Express in iTunes, thus becoming the potential target of streaming audio over WiFi from iTunes. But am I right?

illumin84• 15 years ago

The Airport Express public key was previously known, which allowed anyone to write a program to stream audio to an Apple Airport Express. Now that the private key is known, anyone can write a program to receive audio from iTunes, or from another program that sends to Airport Express.

This means you will be able to easily send audio to other rooms in your house with something like XBMC running on a PC, nettop, or netbook.

edit: Just to clarify - previously you could do this:

iTunes -- stream to --> Apple Airport Express

3rd party software -- stream to --> Apple Airport Express

Now you can do this:

iTunes -- stream to --> 3rd party software/hardware

i386• 15 years ago

Speculation: If iTunes plays the role of the Fairplay DRM decoder and relied on the channel between iTunes and the Airplay device being encrypted to secure content would it now be possible to use the private key to masquerade as a capable Airplay device and dump a the stream pure and DRM free? Would this work for video enabled Airplay devices?

If so, Apple and this hacker are about to be lawyered hard by the MPAA.

brk• 15 years ago

Now you can do this: iTunes -- stream to --> 3rd party software/hardware

How is this all that ground breaking from what you've been able to do with Rogue Amoeba apps for a while now?

http://rogueamoeba.com/airfoil/

PascalW2• 15 years ago

See my comment http://hackerne.ws/item?id=2431331

jedsmith2• 15 years ago

It's dead, Jim!

palish• 15 years ago

The source code is very cool. I'd encourage everyone to skim through it.

Simucal• 15 years ago

Could you provide a mirror? The link seems to be dead.

nettdata• 15 years ago

Just worked for me.

alayne• 15 years ago

I had trouble with DNS not resolving mafipulation.org (without the www). Try http://www.mafipulation.org/static/shairport-0.01.tar.gz

oomkiller• 15 years ago

I uploaded it to Github here in case anyone wants to hack on it: https://github.com/bbhoss/shairport

jameshl3• 15 years ago

Oops, my bad - one of my DNS mirrors was out of date. Thanks for the heads up...

nitrogen• 15 years ago

The rate synchronization code is interesting. Is that what you were referring to?

jedsmith2• 15 years ago

ASCII key, from the source: http://pastebin.com/raw.php?i=RFeUcdXd

peterwwillis2• 15 years ago

The whole source: http://pastebin.com/raw.php?i=mXVK93sY (edit: updated with 0.03)

jameshl3• 15 years ago

Already out of date - 0.03 fixes IPv6. Please, get it from the site (if it hasn't been Slashdotted or something yet :/)

angusgr2• 15 years ago

I know the OP probably isn't reading this, but I'd be curious to know what OS the Airport Express runs.

I always wondered. My guess is maybe a proprietary RTOS to perform its simple functions?

Back in the day I figured it'd make a great OpenWRT Linux box, although now boxes with those features/size/price-point are much more common.

spicyj2• 15 years ago

I think I read somewhere that it uses vxWorks.

jolan2• 15 years ago

The Acknowledgements.pdf file on the software CDROM says NetBSD.

jackolas• 15 years ago

That could mean they're using any amount of NetBSD code, from the networks stack to a single application.

angusgr2• 15 years ago

I asked the OP and they responded to me offline and confirmed vxWorks.

patrickk• 15 years ago

Hadn't heard of vxWorks before. Did a quick googling, it's been used in a huge array of products: Boeing aircraft, industrial robots, Apache attack helicopters, BMW iDrive, Linksys routers, even spacecraft!

http://en.wikipedia.org/wiki/VxWorks#Notable_products_using_...

acgourley• 15 years ago

What are the legal implications of selling a small unit that acts as an airport express, then? And what if you didn't ship the key, but it was obvious to users where to get it?

rhizome• 15 years ago

"Wink wink" has been long dealt with in law. If it's a device that is useless without the key, it'd wind up as a distinction without a difference if Apple really chased this down rather than hiring the devs. "Substantial non-infringing use" is the bar to clear in patent terms.

eru• 15 years ago

Then you should probably ship a small device that a general computer, and there just happens to be some firmware / software floating around on the internet for it.

jrockway2• 15 years ago

Except, streaming music you own to a computer you own is legal regardless of whether or not some piece of propietary software you use has a private key that you aren't supposed to know. The key is out. Using it for anything is legal.

eli5• 15 years ago

I doubt you'd fare much better than running a P2P service that could be used for anything, but was obviously intended for copyright infringement. And that doesn't seem to be doing so hot for Limewire.

daeken• 15 years ago

Hah, awesome. Many years ago, I patched iTunes to use my own public key, so I could stream to an AirTunes server I ran on another machine. I had intended to pull the firmware off the Airport Express, but didn't have the hardware skills at the time. It's awesome to see this happen.

sh1mmer• 15 years ago

There have been a number of manufacturers implementing 'airplay' devices that support being airtunes speakers but it's great to see this making it possible to do with open source. It would be nice to see airtunes added to some of the cheap linux wall warts on the market.

shimonamit2• 15 years ago

So, are there no alternatives to embedding a single private key across multiple hardware devices?

fhars• 15 years ago

You could store the key in a TPM, which would at least require carefully applied stong acids and an electron microscope to dump them.

shimonamit2• 15 years ago

Interesting. So why didn't they use a TMP? Cost savings? International distribution constraints? (I see TPMs are illegal in China -http://en.wikipedia.org/wiki/Trusted_Platform_Module.) It is somewhat peculiar given Apple's known DRM policies.

rdl• 15 years ago

You'd want a combination of storing the keys in tamper-resistant/tamper-responding FIPS 140-2 smartcard module (like a TPM), and some kind of certificated key architecture (where each mac and each airport have a key signed by Apple, but where breaking a single device and extracting the key isn't a class break -- it only provides the ability for everyone to stream to or from that one physical device. That way the Apple Signing Public Key can be in everything, but the Apple Private Key can be kept offline in Cupertino. You could even do a multi-level system where there are manufacturing keys signed by Apple's key so the contract manufacturers don't steal things.

Combine that with a way to update and blacklist keys and devices, and you have the state of the art DRM type system. The cryptography used in the BluRay format is probably about the best currently deployed in that application, and can just be bypassed. The same people (Paul Kocher's Cryptography Research; IMO the top cryptography consultancy in the world) who developed that developed the original Divx system (video rental at Circuit City) did the crypto for BD+. http://en.wikipedia.org/wiki/DIVX

TPMs are unfortunately usually only FIPS 140-2 level 2 or 3, and not THAT hard to break a single instance of. The TCG's TPM architecture is such that compromising one TPM doesn't class break everything. If you naively put a global key into a low-security module like that, and put millions of them in enemy hands, you will get screwed by someone with some acids and an electron microscope at college (or a competitor leaking it anonymously)

Natsu• 15 years ago

I wonder if people will get their IPs subpoenaed for looking at that link, as was the case with the Sony keys?

WiseWeasel• 15 years ago

Meh, they can sue me. I don't think they'll get very far.

eli5• 15 years ago

I'm pretty sure Sony's goal there was to gather information to support their argument that a California court is the right venue and generally to intimidate geohot. Not to sue anyone who merely viewed the page.

yardie• 15 years ago

Sony was using IPs to establish jurisdiction because they have a fairly weak case. AFAIK, you can't be sued for reading/looking at something.

Logicwax• 15 years ago

Works great! Even supports multiple audio streams!

For Debian/Ubuntu users, I had to do a few things to get it to compile: 1. sudo apt-get install libcrypt-openssl-rsa-perl libao2 libao-dev 2. comment out line 642 in hairtunes.c 3. 'make'

cultureulterior3• 15 years ago

And libssl-dev for me on lucid

jameshl3• 15 years ago

Fixed the code bug in 0.02, and added this to the documentation. Thanks!

lawfulfalafel• 15 years ago

I wonder if another aacs controversy is going to rise.

albertzeyer3• 15 years ago

Has someone tried it and was able to play something?

I tried it and iTunes lists it as a device but I cannot activate it in iTunes (if I select it, it immediately unselects itself). From the console output, I see that iTunes even does not try to connect to it (to TCP Port 5000).

I am currently on a Mac so I needed to do some porting (https://github.com/albertz/shairport/) but I think this shouldn't have an impact on the behavior I am getting.

snotrockets2• 15 years ago

Author states this is broken on a Mac.

albertzeyer3• 15 years ago

That is why I have patched it. For example, it uses `dns-sd` instead of `avahi-publish-service`. Registering seems to work, at least iTunes shows it. But there is no single connection attempt, so everything else (all the C-code etc.) is anyway unrelated because it doesn't even get there.

Maybe it refuses to connect because it is the same (localhost) machine? I don't have another machine at hand to try out right now.

rjyo• 15 years ago

I got the same result at first. But after trying to play from my iPod touch, it worked.

I guess running the server and iTunes client on the same machine caused the problem.

My config: MBP on 10.6.7

And thank you for your dns-sd patch on https://github.com/albertz/shairport/

cultureulterior3• 15 years ago

If you disable the IPv6 address on the linux server it works.

cultureulterior3• 15 years ago

Which you can do via, for example

sudo /sbin/ip addr del <ipv6address>/<prefixlength> dev ethX

askedrelic• 15 years ago

Sweet, thanks for your port! I just got everything working on my iMac. It shows up as an AirSpeaker from my iPhone on the same network and I can stream music from the iPhone to my iMac!

albertzeyer3• 15 years ago

With 0.03 and some further fixes, it also works on localhost now.

rafd• 15 years ago

Works great! Many thanks for the port.

kash• 15 years ago

awesome!, now only if we can get forked-daapd to show up under home sharing we'd be set!

kblnig• 15 years ago

i am trying to use the hairport (on apple tv1 running ubuntu hardy)... i am getting the following error:

atv@appletv-ubuntu:~/scripts/bbhoss-shairport-31cf954$ make gcc hairtunes.c alac.c -D__i386 -lm `pkg-config --cflags --libs ao openssl` -o hairtunes hairtunes.c: In function âinit_outputâ: hairtunes.c:642: error: âao_sample_formatâ has no member named âmatrixâ

Could someone help me with this matter :) ?

coffeedrinker• 15 years ago

For those who might not know this, you can stream the audio from one mac to another.

http://www.macgeekery.com/tips/configuration/playing_live_au...

I use it to move music streams to the other computers in the house.

joeshaw• 15 years ago

Does Apple use the same protocol for streaming video to an Apple TV? If so, is the key from an Apple TV needed to emulate a video endpoint, or is just some tweaking required (presumably to the MDNS service data) to identify it as video-enabled?

lloeki• 15 years ago

Video is seemingly not encrypted, only pure audio streams required the key. See Airplayer (http://ericasadun.com/ftp/AirPlay/) and apparently Airfoil Video Player (http://www.rogueamoeba.com/airfoil/mac/) for example.

conradev2• 15 years ago

Video is also an entirely different protocol.

conradev2• 15 years ago

This is awesome! I know many have tried before, but have not been successful.

Also, I thought i would put this out there: As with the creation of the new AirPlay protocol, the RAOP (AirTunes) protocol was also changed (to support album art and other metadata, I assume). My proof of this lies in the Apple TV. If you analyze network traffic between iTunes and the ATV's airtunesd daemon, you can see that the initial pairing does not have the 'rsaaeskey' field but instead a 'fpaeskey' field. So instead of a RSA public/private scheme, it uses something else to encrypt the session keys. I found this out when trying to reverse the airtunesd binary, trying to get the key that way. :P

tobiasbischoff• 15 years ago

Totally want to try this, but my Snow Leopard won't install Crypt::OpenSSL::RSA via cpan, any ideas? http://pastie.org/1783565

gresrun• 15 years ago

Try this:

ARCHFLAGS="-arch i386 -arch x86_64" perl -MCPAN -e 'install Crypt::OpenSSL::RSA'

andrewcooke2• 15 years ago

wasn't this done before, years ago, by Jon Lech Johansen? he wrote justeport - http://nanocr.eu/software/justeport/ (and i rewrote that in java as jjuste, but no longer have the code...)

here are the keys he found - http://nanocr.eu/2004/08/11/reversing-airtunes/ and http://nanocr.eu/sw/justeport/itunesrsakeys.txt

peapicker• 15 years ago

Johansen found the public keys to allow you to stream music to an Airport Express... now we are talking about the private key, which lets you emulate an Airport Express with any hardware that is capable.

andrewcooke2• 15 years ago

ah! thanks! (the idea that someone had to "find" the public keys seems a bit odd, but i guess it was obfuscated?)

blasdel• 15 years ago

A couple years ago I unsuccessfully tried to extract the keys from the AppleTV version of OS X (which provides the same functionality).

The binaries were heavily obfuscated, and I couldn't get the IDA Pro remote to run on the AppleTV, nor could I port the binaries to run on normal OS X. Gave up after a week or so. I figured that some pro reverser would get the keys eventually that way, but I never expected that anyone would find success cracking open an Airport Express!

_3ex7• 15 years ago

cool story bro

Apple AirTunes private key extracted

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